1. Field of the Invention
The present invention relates to an information distribution system such as a video-on-demand (VOD) system. More particularly, the present invention relates to a method and apparatus for adapting at least a service level in response an amount of bandwidth available within the information distribution system.
2. Description of the Background Art
In an information distribution system, such as video on demand (VOD) system, an information provider (e.g., a head-end in a cable television system) must control of the distribution of requested information to ensure that requests for information, such as video information, are satisfied in an orderly manner.
Unfortunately, in an information distribution system serving a large number of subscribers, the bandwidth of the various components forming the information distribution system may, at times, be insufficient to satisfy each subscriber request. Present information distribution systems, such as VOD systems, respond to bandwidth constraints by denying subscriber information requests or providing the requested information in a substantially degraded manner. In a VOD system, this degradation may take the form of poor temporal alignment between video and audio tracks (i.e., poor “lip-sync”), missing information due to “dropped” video or audio frames and/or excessive latency in responding to subscriber interactions. These and other qualitative degradations are common in present systems.
Therefore, it is seen to be desirable to provide a method and apparatus for ensuring that a bandwidth constrained system provides information having at least a minimal qualitative level. Moreover, it is seen to be desirable to provide such functionality within the context of a video on demand system.